QUESTION 6 (4 marks)
a) Explain how energy enters the biotic components of an ecosystem.
[2 marks]
b) Distinguish between gross primary productivity and net primary productivity.
[2 marks]
QCAA guide · typeset solution
QCAA sample response and mark allocation
6a) | Energy enters the biotic components of an ecosystem via photosynthesis, where solar energy from the sun is used to convert carbon dioxide and water into chemical energy in the form of glucose. | • recognises that energy enters the biotic components of an ecosystem via photosynthesis [1 mark] • explains photosynthesis [1 mark] |
6b) | Gross primary productivity (GPP) is the total amount of solar energy converted into chemical energy by photosynthesis, whereas net primary productivity (NPP) is the total energy stored as biomass and made available to consumers. | • describes gross or net primary productivity [1 mark] • distinguishes between gross and net primary productivity [1 mark] |
QCAA sample response and marking criteria reproduced from the official guide.
Compare your working with the guide above.